Documentation

Please contact ch.hill@iaea.org with any questions or comments about this prototype data service.

Identifying Species and States in CollisionDB

The species involved in the CollisionDB processes are identified using the conventions of the pyvalem library:

• Atoms are identified by their element symbols:
  • H
  • Li, etc.
• Molecules are sequences of element symbols, possibly with their numerical stoichiometries given (no underscore characters, _):
  • BeH
  • H2O
  • CH3CH2OH
• Any charges are specfied after the formula in the format +, -, +q, -q (no caret characters, ^):
  • H+
  • Be+4
  • CO3-2
• Isotopes are specified in parentheses, with the mass number preceding the element symbol (no caret characters, ^); deuterium and tritium may be specified as D and T, respectively:
  • (6Li)
  • (13C)

Quantum states are specified in any order using the following conventions:

• Atomic configurations as orbitals separated by a period, .:
  • 1s
  • 1s2
  • 1s2.2s
  • 1s2.2s2.2p4
• Atomic term symbols as follows (2S+1)L_J: spin multiplicity, 2S+1, followed by orbital angular momentum quantum number label and, optionally, J quantum number; odd parity is optionally specified with the character (o):
  • 2P
  • 2Po_1/2
  • 4D
  • 1S_0
• Individual quantum numbers as key-value pairs (no spaces around the = sign):
  • n=1
  • |m|=1
• Linear molecule electron configurations:
  • 1σ
  • 1σ2
  • 1σg2
  • 1sigmau2.2sigmag1
  • 1sigmag
  • 1σg2.1σu2.2σg2.2σu2.1πu4.3σg2
• Molecular term symbols (with or without state labels):
  • 1Σ+g
  • 1SIGMA+g
  • a(3SIGMA-g)
  • X(3Π)
  • X(3PI)
  • A(1A")